What does the “at” (@) symbol do in Python?

Question

I\'m looking at some Python code which used the @ symbol, but I have no idea what it does. I also do not know what to search for as searching Python docs or Goo

Answer 1

If you are referring to some code in a python notebook which is using Numpy library, then @ operator means Matrix Multiplication. For example:

import numpy as np
def forward(xi, W1, b1, W2, b2):
    z1 = W1 @ xi + b1
    a1 = sigma(z1)
    z2 = W2 @ a1 + b2
    return z2, a1